Amp Problem. Need Help

HeavyMetalNyge

I just recently bought a Rivera Clubster 45. Great amp. However, I tried to plug in a pedal that had something wrong with it. Right after that I started having problems with the amp. One of the preamp tubes blew and I replaced it. I thought that was the only problem, but then when I plugged in my pedalboard (which does not have the pedal in question on it) I got a ridiculously loud hum coming from the amp, even though none of the pedals were on. I only have 6 pedals on my board, but for some reason, removing 2 of the pedals relieved the problem. Plugging in only those 2 pedals into the amp also didn't cause any problems. Then I tried plugging in my pedal board with all 6 pedals into another one of my amps and it worked fine, no hum. This leads me to conclude that there is something wrong with the amp and not my pedals or cables. Anyone have any idea what the hell is going on?

Pacomc79

Describe if you can how the preamp tube blew and what the issue is with the pedal in question, could be a red herring.

Personally, I'd get the amp checked out I think. An email to paul rivera wouldn't be a bad idea.

HeavyMetalNyge

It was a Boss MT2 first of all. Well, the pedal never actually worked when I plugged it in. When I would stomp on it, the light would either come on, or blink, or not come on. Sometimes once I got the light on it wouldn't turn off. I never got any noise out of it. As soon as I unplugged it and tried the amp again, the amp sounded like horrible and loud static. Something was definitely wrong, so I took it to the store, and they switched out the reverb preamp tube (is there such a thing? I'm just telling you what they did) and that static went away. But that night when I took the amp to my gig and plugged in my pedalboard, ridiculous hum. Then, like I said, I took 2 of the pedals out (seems as though 4 pedals was the magic # to eliminate the hum) and I was able to make it thru the show. When I got it home, I checked all the cables and all the pedals thru another amp. I tried all 6 pedals thru another amp and I had no problem. Then I tried each pedal individually through the Rivera with no problems. But as soon as I tried all 6, voila, HHHHUUUUMMMM.
I sent the amp to a repair store and, not surprisingly, didn't find any problems. It always happens that way, doesn't it. When you try to show someone the problem it doesn't happen. Anyways, I'm supposed to pick up the amp from the store today or tomorrow. I'm going to take my pedal board with me and if the problem is still there, I'm returning that bitch.

Pacomc79

hmm, so they replaced the 12AT7 Preamp tube that could certainly be the cause of noise and the other tubes could be microphonic but it might more likely be a grounding issue somewhere.

Definately email rivera. They are way way smarter than me. sometimes these things have to do with cable impedence issues, or loose joints in the pedals.

Does the amp work without the pedalboard? If so plug each in individually, and use process of elimination.

exhausted

what's in the pedal chain and how are they being powered?

HeavyMetalNyge

Turns out it was a bad AC adapter in my chain. Still don't understand something though. I had that amp and another one side by side, and my pedalboard caused a humming noise in the amp in question but not the other one. I don't get it, but whatever.

Pacomc79

HeavyMetalNyge wrote:

Turns out it was a bad AC adapter in my chain. Still don't understand something though. I had that amp and another one side by side, and my pedalboard caused a humming noise in the amp in question but not the other one. I don't get it, but whatever.

Was the other amp solid state?

The humming is caused by something called a ground loop, it's a 60 cycle hum. The other amp may be shielded better from the ground loop than the Rivera for a variety of reasons. Usually when you have a pedal problem causing hum it's from a ground loop or a dirty power source such as your adaptor, this is the reason people spend the big money to use isolated power supplies like the Voodoo Labs Pedal Power 2 or the Juice Box. You can also use hum eliminators and EMI/RFI power conditioning in some applications. Unfortunately the bad power problem is pretty common. I use a daisy chain power source from Switchmode and I've never had a problem but the PP2 is pretty much the industry standard best available option. Glad you found the problem and it works now.

HeavyMetalNyge

Thanks. No, the other amp wasn't solid state. I actually tried it through 2 other amps. One was my peavey classic 50, and the other was my marshall jcm 900. No hum in either one, just in the rivera.

Pacomc79

HeavyMetalNyge wrote:

Thanks. No, the other amp wasn't solid state. I actually tried it through 2 other amps. One was my peavey classic 50, and the other was my marshall jcm 900. No hum in either one, just in the rivera.

were all of the amps plugged in to the same outlet or an any proximity to flourescent lighting? That can sometimes cause it, but if the adaptor fixed it I wouldn't be overly concerned until you have the problem again. Bob used to own a Rivera, maybe he will know.